The present invention relates to an internal combustion rotary engine.
Conventional internal combustion piston engines, used for powering motor vehicles and power generators and in numerous other applications have many shortcomings.
To understand some of these shortcomings, one need only review the sequence of events in a single piston engine. Combustion of the air/fuel mixture in the cylinder head commences just before the piston reaches top dead center, to have good pressure applied when the connecting rod is at its most efficient position on the crankshaft (90xc2x0). Therefore, depending upon flame front progression and the rpm of the engine, most of the high pressure occurs when the crankshaft lobe is still just off a vertical axis of the shaft center in the 10xc2x0 range. This results in much of the downward force from the piston being diverted from efficient rotary movement to the application of vertical pressure on the crankshaft""s main bearings. Only when the lobe of the crankshaft is at 90xc2x0 to the center line of the main shaft is positioning ideal to transfer the piston""s vertical force into rotary motion. At this position, however, combustion has already occurred and, as the volume of space in the cylinder has increased to one half total displacement, much of the high pressure energy from the combustion has been dissipated.
In following the sequence of events following the power stroke, including the exhausting of gases and the intake of more air/fuel mixture and compression, it should be understood that all of these steps require piston movement in either a two or four stroke engine design. These actions are dead loads requiring rotary energy to be taken back from the crankshaft. This sequence explains why engine manufacturers"" efficiency ratings under ideal conditions are generally less than 35% for such internal combustion engines.
Rotary engines, such as the WANKEL (trade-mark) are attempts to address these and other problems inherent in such piston driven internal combustion engines. The idea is to provide a high torque rotary shaft powered more directly by the forces generated by the ignition of the gas/air mixture. In the case of a WANKEL engine, instead of pistons, a cam surface mounted on a rotary shaft and housed within a combustion chamber provides a replacement for pistons.
In applicant""s co-pending U.S. patent application Ser. No. 09/973,782, a fluid turbine is described and illustrated having vanes protruding from a rotor at right angles to the center line of the drive shaft. The construction of that turbine enables an excellent seal between adjacent compartments and, because support for the vanes is provided at their sides, a strong, non-binding configuration is achieved. The turbine is capable of providing a more efficient conversion of energy because of the direct application of the force of the incoming fluid on the vanes. It permits the rotor to be under full power and under force of the fluid entering the inlet over one half of a revolution.
It is an object of the present invention to adapt the principles of such a turbine to provide a more efficiently operating internal combustion engine, and to use that technology in a number of different applications.
In accordance with the present invention there is provided an internal combustion rotary engine, which comprises a rotary device having a rotor, with ends and a cylindrical sidewall, and a housing encasing the rotor. A rotor disk is provided at each end of the rotor to rotate therewith. The housing has interior end walls confronting the rotor ends, interior sidewalls and fluid inlet and fluid outlet ports. A first portion of the interior sidewall of the housing is cylindrical and curved with constant radius over an angle of approximately 180xc2x0. This first portion of the interior sidewall is spaced a constant distance from corresponding portions of the wall of the rotor. A second portion of the interior sidewall of the housing continues from the extremities of the first portion and has a curvature of greater radius. The wall of the rotor meets the interior wall of the housing at a point between inlet and outlet ports about midway on this second portion. The inlet and outlet ports are located in this second portion of the interior sidewall of the housing. Two or more vanes having inner and outer ends extend parallel to the axis of the rotor and are movable radially inwardly and outwardly between retracted and extended positions with respect to the cylindrical sidewall of the rotor within slots in the rotor. The vanes have side shoulders, which slide in corresponding guide slots in the rotor disks. The outer ends of the vanes are positioned adjacent the inner wall of the housing and the vanes are spaced, preferably, equally from adjacent vanes about the rotor such that there is always at least one vane positioned between the inlet and outlet ports. Means are provided to move each of the vanes radially within its associated rotary slot between an extended position and a fully withdrawn position so that the outer extremity of each vane is positioned adjacent a corresponding portion of the inner wall of the housing. The rotor, housing and vanes are constructed so that, during operation of the device, fluid entering the housing drives the rotor and is carried by the rotor in compartments formed between adjacent vanes, the rotor sidewall between those vanes and corresponding portions of the sidewalls of the housing until the adjacent vanes encompass the outlet port whereby the fluid is allowed to escape. In addition, the engine comprises a combustion chamber communicating with the fluid inlet port and an exhaust chamber communicating with the fluid outlet port. Air and fuel injection means are associated with the combustion chamber for delivery of an air and fuel mixture to the combustion chamber. Igniter means are associated with the combustion chamber for igniting air and fuel mixture within that chamber. The exhaust chamber is provided with an exhaust valve, which closes to seal the chamber, and opens to permit exhaust gases in the chamber to escape. Means are provided to properly control the sequence of air and fuel injection, fuel ignition and exhaust valve opening and closing during operation of the engine.
In a preferred embodiment, the engine is arranged so that the combustion chamber can function as an exhaust chamber, and the exhaust chamber as a combustion chamber, whereby the rotor can be turned in an opposition direction.
The rotary engine according to the present invention is simpler and more economical to manufacture than conventional rotary engines, and has fewer components. Hence it is lighter in construction and requires less space.